docs: def _get_magnitude_term(self, C, mag):
          """
          Returns the magnitude scaling term.
          """
          lny = C['C1'] + (C['C3'] * ((8.5 - mag) ** 2.))
          if mag > 6.3:
              return lny + (-C['H'] * C['C5']) * (mag - 6.3)
          else:
              return lny + C['C2'] * (mag - 6.3)